Cracking hydrocarbon oil



Sept. 1, 1942. w. E. LEMEN CRACKING HYDROCARBON OIL Filed April 6, 194C4 II'and valve I2.

Patented Slept. 1y, 1942 UNITED STATE s PATENT oFFlcE CRACKINGHYDROCARBON OIL William Edward Leinen, Chicago',

Universal Oil Products Company, Chicago,

IIL, assignorto Ill.,

a corporation oi Delaware l Application April 6, 1940, Serial No.v328,166

4 Claims;

This invention 4relates to a process for converting hydrocarbon oilscontaining substantially noy gasoline into motor fuels of high antiknockvalue. More specically the process relates to an improved method forcracking petroleum oilsand similar charging stocks inthe presence ingcatalyst, passing the higher and lower boiling v fractions to a reactionzone, removing vaporous products therefrom to a fractionating zone,passing liquid reaction products' containing catalyst in suspension to avaporizing zone, passing the vaporous reaction products therefrom' to'said fractionating zone, recovering the' spent catalyst from saidvaporizing. zone, separating gasoline and gas Vfrom said fractionatingz'one, mixing a higherboiling fraction of insuiiiciently converted oilwith/powdered catalyst, heating the mixture and passing it to saidreaction zone for further conversion as previously indicated, heating alower boiling fraction in the absence of catalyst and. supplying it yforconversion as previously mentioned.

The process is illustrated diagrammatically in the accompanying drawingwhich should not be interpreted as limiting it to the exact apparatus orconditions shown therein. The apparatus is I4. An Aintermediate boilingfraction is removed from the fractionatorthrough line I5, valve I6, pumpIland valve I8 to coil I9 which is disposed in 'heater a crackingtemperature within the range of approximately 800-1200 F. and passedthrough line 2l and valve 22 to reaction chamber 24. A

l higher boiling fraction of oil is removedv from fractionator 6 throughline 25, valve 26, pump 21 and valve 28 and is mixed with powderedcracking catalyst from catalyst charger 29, the catalyst enteringthrough line 30, valve 3|, pump 32 and valve 33, joining with line 25.The catalyst may be suspended in a portion or all oi the charging rstock or in an intermediate boiling 'fraction of hydrocarbon oil. Themixture of the higher boiiing fraction of charging stock and catalystpasses through line 34 and valve. 35 to coil 36 which is disposed inheater 31. The mixture is heated to a cracking temperature and pressure,the temy perature being below that at whichv the crack- ,ing reactionbecomes, excessively rapid, usually y within the range of approximately500-1000 F.

and a pressure of approximately 50-1000 pounds per square inch. Theadditional heat required is supplied by the intermediate boilingfraction from line 2|.` TheI reaction mixture passes through line 38 andvalve 39 and thence to reaction chamber 24. A liquid level may bemaintained in the reaction chamberwhlch is operated 'at a temperatureWithin l. the t range ofv approximately 500-1000 F. `or higher andv apressure of 10D-1000 pounds persquare inch. The maintenance of a liquidlevel in the reaction chamberr permits adeshown in side elevation andhas not been drawn to scale, nor has any attempt been made to profportionate the various parts of vthe equipment exactly. y l

A charging stock which may comprise crude oil or topped crude oil, butis preferably a distillate fraction of a crude hydrocarbon oil, isintroduced through line I, valve 2, pump 3, valve 4 and line 5 tofractionator 6. If a crude oil containing substantial quantities ofgasoline is used, the gaso- Y line, together with the cracked gasolineand gases produced as hereinafter described, is removed through lineI,valve 8,-condenser 9 to receiver lofi-om which gases are removed tosuitable absorption equipmentl not shown through-inne The gasoline maybe removed quat contact of the hydrocarbon oill ,with the powderedcatalyst. The reaction products are in- `troduced at a point below thesurface of the liquid which prevents the catalyst `vfrom settling fromthe oil while in the chamber.

The particular advantage of this operation is that additional heat maybe supplied tovthe reaction chamber by means of the lighthydrocarbonfraction which is heated in coil I9.

Vapors from the reaction chamber are removed through line 40 and valve4I to line 5 and thence to fractionator 6. The liquid portion ofreactionv products containing catalyst in suspension is withdrawnthrough line 42 and valve 43-to vaporizingchamber ,44' which ismaintained at a substantially lower pressure than reaction chamber 24.The major portion of the material is vato a stabilizer not shoyvnvthrough line I3 and valve 55 porized at this point and passedthroughline and valve 46 which joins with line 40 and is passed to thefractionator 6. As in the case of reaction chamber 24a liquid level maybe maln- 20. This oil may be heated to tained in vaporizng chamber M inorder to obtain additional beneilt of the catalyst and to prevent thecatalyst from separating and plugging the lines. A portion or all of theheated low boiling fraction from line 2i may be passed vthrough line 23and valve 23 to line 42 and valve B3 to supply additional heat andassisty in vaporizing the oil in chamber 44. Residue containing catalystin suspension is removed through line 47 and valve 48 to catalystrecovery system not shown. from theoil by filtering or other suitablemeans, and reactivated by treatment with an oxygencontaining gas at atemperature Within the range of approximately 80G-1500 F.

Cracking catalysts suitable for use in the present operation maycomprise the so-called silicaalumina, silica-zirconia,silica-alumina-zirconia type catalyst which may be or may not containsmall quantities of boron oxide or other agents to improvethe catalyticaactivity thereof. Composites of this type are prepared` by the separateor simultaneous precipitation of the component parts followed by washingand drying under such conditions that alkali .metal ions are substan-The catalyst is separated tially removed. The catalyst is used in theform, i

of a nely divided powderpreferably approaching colloidal dimensions inorder to obtain a high y' R degree of catalytic surface and t0 preventan undue amount of settling at various points in the equipment.

Other cracking catalysts may be used such as e `naturally-occurringearths or naturally occurring earths which have been treated with acidor other chemicals to increase their catalytic activity.

Still another type of catalyst comprises relatively inert carrierssuch'as alumina, magnesia, titania, zinc oxide, etc., having depositedthereon relatively minor amounts of the oxides or suldes of molybdenum,chromium, vanadium, etc.A This type of catalyst may als'o be mixed invarying proportions with silica-alumina, silica-zirconia, etc., type ofcatalyst. J /v The catalytic agents mentioned present process are notnecessarily equivalent in the'reactions they promote or in the yield ofdesirable products obtainable. Theyvary considerably incatalyticactivity and the optimum temperature and pressure conditions,for eachcatalyst is not necessarily the same. r

The following'example is given to illustrate the forvuse in theusefulness and practicability of the process, but j should not beconstrued as limiting it to the exact conditions or'catalysts lusedtherein. l

A,Pennsylvania' distillate boiling in the range lof approximately40G-760 F. may be treated in themanner described in the foregoingspeciilcation wherein a light oil side cutof approximately kerosenebiling range is processed in the light oil coilv and the residualportion is mixed with,l

approximately 2% by weight of silica-alumina cracking catalyst powderfor treatment in the heavy oil coil. 'I'he light oil fraction is, heatedto a temperature of approximately 975 F. under a pressure ofapproximately 500 pounds per square inch. 'I'he heavy oil fraction isheatedto approximately 800 F. under a pressure 4of 200 A Pound);` persquare inch. The reaction chamber'- is maintained at a temperature of'approximately v S50-875 Il'.l and a pressure of 175 pounds per squareinch. Vaporous reaction products are removed to the fractionator and theliquid products containing catalyst in suspension are passed to thevaporizing chamber which is maintained at a pressure of approximately 50pounds per square inch. A total yield of gasoline amounting to '12%'ofthe original charging stock may be obtained in this way. An additionalquantity is obtainable by polymerization of the normally gaseous olenscontained in the gases.

I claim as my invention:

1. A hydrocarbon oil .conversion process which comprises fractionatingthe charging oil together with cracked 'vapors'formed in the process ina fractionating zone, removing from said zone a relatively heavycracking stock and a lighter cracking stock, commingling a powderedcracking catalyst with the heavy stock and heating the mixture to atleast 500 F. in a heating zone, discharging the heated mixture into areaction zone, thermally cracking said lighter stock in a. secondheating zone at higher temperature than that to which said mixture isheated in the firstnamed heating ezone, discharging resultant heatedproducts ln`to the reaction zone andtherein transferring heat from saidproducts to said mixture, removing vapors from the reaction zone andsupplying the same to the fractionating.

zone, and finally condensing the fractionated vapors. y l

2. A hydrocarbon oil conversion process which comprises fractionatingthe charging oil together with cracked vapors formed in the process in afractionating zone, removing from said zone a relatively heavy crackingstock and a lighter cracking stock, commingling a powdered crackingcatalyst with the heavy stock and heating the mixture to at least 500 F.in a heating zone,

vdischarging, the heated mixture into` a reaction finally condensing thefractionated vapors.

l 3. A hydrocarbon oil conversion process which comprises commingling apowdered cracking catalystr with a relatively heavy oil, introducing theresultant mixture to a reaction zone maintained under catalytic crackingconditions, simultaneously subjecting a lighter oil to thermal crackingat highertemperature than that maintained in the reaction zone,discharging resultant heated products into the reaction zone and thereintransferring heat from said products to said mixture to supply heat forthe catalytic crackingoi' said heavy oil, removing vapors from thereaction zone and fractionating and lcondensing the same, separatelyremoving admixed unvaporized oil and catalyst from the reaction zone andintroducing"` the same to'a reduced pressure vaporizing zone,- anddischarging additional heated productsfromthe thermal cracking step intosaid vaporizing zone .to assist the vaporization of oil from catalysttherein.

4. Thev process as dened in claim 3 further characterized in that vaporsevolved in the vaporizing zone are combined with the vapors from thereaction zone for fractionation andv condensation therewith. v

